The invention relates to an air charging manifold arrangement for a multi-cylinder combustion engine which has its cylinders arranged in a boxer or V-configuration with two similar cylinder groups disposed oppositely of one another.
According to a known combustion engine (DE-OS No. 1,939,049), the intake manifold is so formed for the oscillating charging air that a standing half wave is formed. The nodes of this half wave are disposed at the connecting point of a perpendicular extending suction connection piece, while the maximal half wave is contiguous to the suction pipes of the cylinders, for example, at the inlet valves. In an especially space-saving emboidment, the bent or folded single suction pipes are connected outwardly in respectively two groups at two pipes, centrally of which a common connection pipe protrudes inwardly and contains the suction pipe connection. This arrangement is disadvantageous because of the high loss of stream flow resulting from the double turning around of the suction air and because of a poor filling rate of the cylinder which leads to a significant load decrease of the combustion engine. Furthermore, the flow path to the individual cylinders is differentially long so that there is a resultant corresponding differential loading.
A problem contemplated by the invention is the development of an air intake manifold arrangement with the smallest feasible throttling losses and which facilitates a correspondingly similar filling or charging of all of the connected cylinders.
A solution of this problem is advantageously obtained according to the invention by providing that the air suction manifold is formed as an "I" shaped distribution piece with two resonance chambers connected by a straight connecting pipe, with straight parallel pipes leading from the respective resonance chambers to cylinders of associated cylinder groups, and with a suction connection fitting extending perpendicularly to and connected with a single opening to the connecting pipe.
In especially preferred embodiments at the oppositely disposed walls of the resonance chambers the straight single suctin pipes for each cylinder group are so connected that they are symmetrical and parallel at the connecting pipe. By means of a predetermined relationship between the volume and distance from the centerline of the suction connection fitting, a half wave is formed in the distributing piece, which halfwave has a pressure maximum at the connection position of the single suction pipes at the adjacent resonant chambers. The incoming air through the suction connection fitting in the distributing piece can flow through in straight paths without noticeable travelling losses to the inlet valves of the cylinders. Through the symmetrical arrangement of the individual suction pipes the stream path for all cylinders is similarly long so that there results also similar filling or charging rates and similar loading for all cylinders.
Because the perpendicular connection of the suction connection fitting at the connecting pipe forms an effective neutralization of the oscillations formed in the distributing piece from the oscillations in the inlet part from the air filter to the suction connecting filling, the volume and the length of the distribution piece can optimally be arranged with respect to the cylinders so that adjustment of charging defects over a large rotational regime of the combustion machine is obtained. The optimum results are obtained when the total volume of the resonance chambers is slightly smaller than the entire working volume of the cylinders. When the distance between one resonance chamber to the middle of the suction connection fitting is smaller than the distance to the other resonance chamber, according to the invention its volume is correspondingly increased so that the product of the volume and the distance remains respectively constant. The illustrated preferred embodiment of the invention involves a six-cylinder boxermotor.
Further objects, features, and advantages of the present invention will become more apparent from the following description when taken in connection with the accompanying drawing which shows, for purposes of illustration only, a single embodiment in accordance with the present invention.